The present invention relates to multicomponent fibers comprising starch and polymers. The fibers will have high elongation and can be used to make nonwoven webs and disposable articles.
There is a desire to provide low-cost fibers that have improved elongation or extensibility. There is also a desire to provide such fibers that incorporate polymer components derived from biorenewable resources. There is also a need for nonwovens that can deliver softness and extensibility. Nonwovens that are capable of high extensibility at relatively low force are also desired. These can be used to provide sustained fit in products and facilitate the use of various mechanical post-treatments. Typically, it has been found that extensibility is difficult to achieve without an increase in the expense of producing the fiber. Typical ways of increasing fiber extensibility include using high-cost materials and or special, often costly, mixing requirements.
There exists today an unmet need for extensible nonwovens that can be made with thermoplastic polymers. The present invention provides extensible fibers that can be cost-effective and easily processable. The fibers are made of a combination of starches and thermoplastic polymers. The starch and polymer composition is suitable for use in commercially available equipment used to make the multicomponent fibers.
The present invention is directed to multicomponent fibers. The multicomponent fibers will comprise a core component comprising thermoplastic starch which is encompassed by thermoplastic polymer component comprising a non-starch thermoplastic polymer. The configuration of the multicomponent fibers will be of a sheath-core configuration wherein the thermoplastic polymer component constitutes the sheath and the thermoplastic starch component constitutes the core component. The core component can have a single core, or two or more cores. The multicomponent fibers will have a greater elongation than the same thermoplastic monocomponent fibers produced under identical processing conditions.
The present invention is also directed to nonwoven webs and disposable articles comprising the multicomponent fibers. The nonwoven webs may also contain other synthetic or natural fibers blended with the fibers of the present invention.